1. Field of the Invention
The present invention relates to a gallium nitride (GaN) substrate.
2. Related Background Art
A substrate composed of single crystal nitride semiconductor is disclosed (cf. Japanese Unexamined Patent Application Publication No. 2006-044982). This substrate includes AlXGa1-XN (0≦X≦1) in composition and has a fracture toughness value of more than or equal to (1.2−0.7×) MPa·m1/2. A primary surface of the substrate has an area of more than or equal to 20 cm2.